First thing is you have to find out if the arena has holes in the glass for photographers. If not you have to get rid of the lens hood and press the lens against the glass. I have a feeling 150-600 would be too long. Generally 70-200 does better.

Focusing is the hardest part as ice hockey moves super fast. My Nikons has a mode called dynamic focusing or something where it will focus on anything that comes in to that area. Use whatever equivalent of that in canon, shoot burst mode, if you don’t have a huge card shoot jpg. No e-shutter. Keep a high shutter speed. If you have a wide angle lens like 14-24 you can get some cool shots. Also if you are shooting through a hole be very aware as that puck will leave a hole in your head if you get hit. Also people will bump into the glass hard so be aware otherwise you’ll get a knock on your forehead from your camera.

Don’t worry too much about the wb or exposure. Auto modes on your camera will do a pretty good job of figuring that out